The Gothic style of architecture first emerged in Northern France during the 12th century. In engineering terms, it was a major step forward from the Romanesque style that had dominated European architecture up to that time. It allowed people to construct cathedrals, churches and other buildings on a scale that dwarfed anything that had gone before. The technological superiority of the Gothic approach was the result of three engineering breakthroughs: the pointed arch, the ribbed vault and the flying buttress.
The most immediately recognizable feature of Gothic architecture is the pointed arch. This can be seen in windows, doorways and the arcading between supporting columns, and it represents a significant departure from the semicircular arch of Romanesque architecture. The utility of the latter was limited because the height of the arch always had to be exactly half its width. In contrast, a pointed arch can have any ratio of height to width. Besides this practical advantage, the pointed arch offers benefits in terms of structural engineering: A greater proportion of the weight above the arch is channeled down into the ground, instead of exerting a sideways force.
The stone ceilings of Romanesque buildings took the form of semi-cylindrical barrel vaults. These were heavy and inefficient, and placed severe limitations on the size of buildings that could be constructed. The situation changed dramatically with the advent of the Gothic style. This used a web of intersecting stone arches, called ribs, to provide the strength, while the space between the ribs was filled with lighter stonework which was not load-bearing. As long as care was taken to channel the weight of the ribs down through columns to the ground, there was virtually no limit to the maximum size of edifice that could be built.
A buttress is a heavy pillar of stone built up against an outside wall to counter forces – either from air turbulence or the weight of masonry – pushing sideways on the wall. This assumes, however, that the wall extends vertically all the way to the ground. In many Gothic buildings this was not the case, because the upper tier was narrower than the lower tier. This meant the supporting pillar for the upper part of the wall had to be built some distance away from the wall, and then connected to it by a load-bearing arch. The resulting combination of pillar and arch is called a flying buttress.
The greatest achievement of Gothic architecture can be seen in the magnificent cathedrals of medieval Europe, including those of Chartres in France, Cologne in Germany and Milan in Italy. The engineering innovations of pointed arches, ribbed vaults and flying buttresses meant such buildings could be the longest, widest and tallest of their day. Even in modern times, the Gothic approach is unsurpassed as far as solid stone buildings are concerned. The National Cathedral in Washington D.C. was constructed during the 20th century using exactly the same techniques as the great Gothic cathedrals of the Middle Ages.